Laser apparatus generally requires that in addition to the material which is, or is to form, the laser active medium, a buffer gas or mixture of gases is also included within a discharge tube to enable sufficient gas pressure to be maintained for laser action to be possible. It has been found that the introduction of small quantities of hydrogen into a buffer gas, such as neon, may improve the operating efficiency of the laser in some cases, although the mechanism by which such an introduction facilities the laser action is not at present clearly understood. Other gases such a deuterium, nitrogen and oxygen may also give increased efficiency when added to a laser active medium and buffer gas. The quantities required for such efficiency enhancing gases to be effective are generally much smaller than the main buffer gas or gases, a typical arrangement having partial pressure of one hundred times less than the main buffer gas pressure.
The present invention arose from a consideration of the use of hydrogen or other efficiency improving gases in laser arrangements.